Ross Brawn has defended the number of high-profile Mercedes technical staff, saying the current structure is necessary in order to run two parallel projects on the 2013 car and 2014 car.

Mercedes currently has four ex-technical directors from other teams in its ranks, with Brawn heading up the outfit as team principal, Bob Bell as technical director, Aldo Costa as chief designer on the 2013 car and Geoff Willis overseeing work on 2014. Brawn said the current structure was part of his plan for the future of the team and was necessary to fight successfully over the next two years, especially with the change in engine regulations for 2014.

"I think the structure we have now is the structure that I designed in 2012," he said. "So Bob Bell is the technical director and Bob's been our technical director for a number of years. It's quite clear that there are other demands on the engineering team, particularly when you are looking at a new car as we are in 2014.

"The new car is so dramatically different to the existing car that it was essential that we have parallel engineering groups, closely linked together, but parallel groups to do the current car and the new car. The new car is headed up by Geoff Willis and the current car is headed up by Aldo and that gives us the strength to do both programmes.

"As an engine manufacturer we have to have a lot of input into the engine to get it right for the chassis. So if you were a simple customer you would take what the engine supplier gives you, but if you are what we are - a complete team - our group has had to be working on the car perhaps much earlier than other teams because we have to understand what engine we want for the car. That parallel activity is essential and I think Ferrari announced a short while ago that they have two teams working on '13 and '14 and that's what we've done. Perhaps the names we have are a bit more widely known, but it's the essential structure that you need to support those programmes."

Brawn said the plan was to fight with the top teams throughout 2013 and that the new structure would allow Mercedes to fight until the very last race.

"It's not our plan to reduce our effort on the '13 car at any stage during this season," he said. "We want to put maximum pressure [throughout]; that was where we were weak in 2012, we started strong and then we faded. We don't want to fade in 2013. We're planning and structuring to be able to support the 2013 car all the way through the year. Inevitably if you reach a point where there is nothing to be gained by doing that then you have different priorities, but the plan is to push hard throughout the year."

Rumours last month suggested McLaren technical director Paddy Lowe could also be on his way to Mercedes, but Brawn did not want to be drawn on the issue: "He's with McLaren this year, that's what McLaren has announced. I've nothing to add to that, I'm afraid."

Part of the same story was that CEO Nick Fry would be muscled out, but Brawn said he expects Fry to stay.

"Nick's been a key member of the team and we've got a new sponsor this week [Blackberry] and Nick's been very involved in that. Nick I'm sure will be involved in the team in the future, but perhaps in a different role."

Brawn also revealed that ex-Mercedes driver Michael Schumacher would continue in an ambassadorial role on the road car side of the company.

"Michael's carrying on in an ambassadorial role, so he's going to have some involvement in the commercial activities," Brawn said. "Mainly within the car company as opposed to the race team, but I've spoken to Michael a few times and he's still got enthusiasm and wants us to do well. It will almost exclusively be to do with the car company, the development of high-performance models, so he'll still be part of the family but in a different position."